The observables in Table REF  are obtained by integrating over \(\nu \)  the nucleon polarized structure functions
\(g_1\)  and \(g_2\)  [1]}. To reach low \(Q^2\)  while keeping the wide \(\nu \)  range
necessary for the integration, a high-energy beam (here up to 4.4 GeV) is needed and the scattered electrons
must be detected at small angles
(here, down to about \(6^\circ \) ). These angles were reached in Hall A thanks to a new horizontally-bending dipole magnet
placed in front of the spectrometer [2]}. In Hall B, a dedicated Cherenkov Counter optimized for high efficiency
at small angle was added to one of the six sectors (otherwise identical) of the spectrometer [3]}.
In addition, the Hall B target was moved 1 m upstream of its usual position and the spectrometer magnetic field was set
to bent the electrons outward.
E97110 studied the spin structures of the neutron and \(^3\) He thanks to the Hall A polarized \(^3\) He target, using
both its longitudinal and transverse polarization capabilities. In particular, the latter allowed to measure \(g_2\) , which is crucial to form \(\delta _\mathrm {LT}\) .
E03006/E05111 studied the proton, deuteron and neutron spin structures with the Hall B longitudinally
polarized ammonia (NH\(_3\)  or ND\(_3\) ).
